CN117396711A

CN117396711A - Refrigeration cycle device

Info

Publication number: CN117396711A
Application number: CN202180098476.1A
Authority: CN
Inventors: 行德骏哉; 门胁仁隆; 伊藤正紘
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2021-05-27
Filing date: 2021-05-27
Publication date: 2024-01-12
Also published as: JPWO2022249394A1; WO2022249394A1; EP4350253A1

Abstract

A refrigeration cycle device (100) is provided with a refrigerant circuit (80) and a non-azeotropic refrigerant flowing through refrigerant pipes (51-56). When the non-azeotropic refrigerant passes through the outdoor heat exchanger (40), a temperature difference is generated between the inlet and the outlet of the outdoor heat exchanger (40). The outdoor heat exchanger (40) is provided with fin groups (L1, L2) stacked at intervals, and heat transfer tubes (R1-R12) which penetrate the fin groups (L1, L2) in the stacking direction of the fin groups (L1, L2) and flow a non-azeotropic refrigerant therein. The fin group (L1, L2) is provided with A1 st fin part (A1) capable of adhering frost in a humid environment and A2 nd fin part (A2) capable of ensuring ventilation without adhering frost.

Description

Refrigeration cycle device

Technical Field

The present invention relates to a refrigeration cycle apparatus.

Background

In recent years, it has been demanded to use a refrigerant having a low GWP (global warming potential). However, it is difficult to achieve both of the lowering of GWP and the maintenance of performance, and in order to compensate for the length of the refrigerant, a mixed refrigerant in which two or more kinds of refrigerant are mixed is studied. It is known that in the case of a non-azeotropic refrigerant mixture in which refrigerants having different boiling points are mixed, an inclination occurs in an isotherm in a two-phase region on a p-h diagram.

Japanese patent application laid-open No. 2018-21781 (patent document 1) discloses a refrigeration cycle apparatus that uses a zeotropic refrigerant mixture, in which imbalance in temperature distribution across an evaporator is reduced.

Prior art literature

Patent literature

Patent document 1: japanese patent application laid-open No. 2018-217421

Disclosure of Invention

Problems to be solved by the invention

For example, in a low-temperature and high-humidity heating operation performed before and after an outside air temperature of 2 ℃, there is a concern that the heating capacity may be reduced due to frosting. Therefore, in general, when an air conditioning system is introduced, a system design is performed in advance so that a sufficient margin is provided for maximum capability that can be exhibited in a frostless state under low-temperature and high-humidity conditions. Further, when frosting occurs, the refrigerant circulation amount is increased by increasing the operation frequency of the compressor, so that the deterioration of the heating capacity due to frosting is avoided.

However, when the compressor frequency is maximized and the capacity is reduced due to frosting, the defrosting operation is performed. During this period, the low-temperature refrigerant flows into the load side, and the temperature decreases, which deteriorates the comfort on the load side. Further, since the defrosting cycle, which is a cycle obtained by adding up the heating operation time and the defrosting time after 1 time, becomes short, there is a problem that the cumulative heating capacity is lowered and the average coefficient of performance (Coefficient Of Performance:cop) is lowered. In the heating operation at the time of low temperature and high humidity, the evaporation temperature of the refrigerant is lower than that of the outside air, and thus, frosting cannot be avoided, and therefore, a technique for extending the defrosting cycle while suppressing frosting is required.

The invention aims to provide a refrigeration cycle device capable of inhibiting frosting and prolonging a defrosting period.

Means for solving the problems

The present invention relates to a refrigeration cycle apparatus. A refrigeration cycle device is provided with: a refrigerant circuit in which a compressor, a condenser, a1 st expansion valve, and an evaporator are connected by refrigerant piping; and a non-azeotropic refrigerant flowing through the refrigerant pipe. In the case where a non-azeotropic refrigerant passes through an evaporator, a temperature difference occurs between the inlet and the outlet of the evaporator. The evaporator is provided with: fin groups stacked at intervals; and a heat conduction pipe penetrating the fin group in the stacking direction of the fin group, for allowing the zeotropic refrigerant to flow therein. The fin group includes: a1 st fin portion capable of adhering frost in a multi-wet environment; and a2 nd fin portion which ensures ventilation without adhering frost.

Effects of the invention

According to the refrigeration cycle apparatus of the present invention, in the low-temperature and high-humidity heating operation, frosting can be suppressed, and the defrosting cycle can be prolonged, so that the load-side comfort can be improved.

Drawings

Fig. 1 is a diagram showing a configuration of a refrigeration cycle apparatus according to embodiment 1.

Fig. 2 is a p-h diagram of a refrigeration cycle apparatus in a study example using an azeotropic refrigerant.

Fig. 3 is a view showing a frosting zone of the outdoor heat exchanger in a study example using an azeotropic refrigerant.

Fig. 4 is a p-h diagram of the refrigeration cycle apparatus of the present embodiment using a non-azeotropic refrigerant.

Fig. 5 is a diagram showing the structure and frosting area of the outdoor heat exchanger of the present embodiment using a non-azeotropic refrigerant.

Fig. 6 is a view of the outdoor heat exchanger shown in fig. 5, as seen from the front.

Fig. 7 is a diagram for explaining a difference in defrosting cycle between a study example and the refrigeration cycle apparatus of the present embodiment.

Fig. 8 is a diagram showing a configuration of a refrigeration cycle apparatus according to embodiment 2.

Fig. 9 is a diagram for explaining the configuration of the temperature sensor 111.

Fig. 10 is a diagram for explaining the determination of the mounting position of the temperature sensor 111.

Fig. 11 is a flowchart for explaining the processing executed by the control device in embodiment 2.

Fig. 12 is a p-h diagram for explaining a change in the refrigeration cycle in embodiment 2.

Fig. 13 is a diagram showing a configuration of a refrigeration cycle apparatus according to embodiment 3.

Fig. 14 is a flowchart for explaining the processing executed by the control device in embodiment 3.

Fig. 15 is a p-h diagram for explaining a change in the refrigeration cycle in embodiment 3.

Fig. 16 is a diagram showing a structure of a refrigeration cycle apparatus according to embodiment 4.

Fig. 17 is a flowchart for explaining the processing executed by the control device in embodiment 4.

Fig. 18 is a p-h diagram for explaining a change in the refrigeration cycle in embodiment 4.

Fig. 19 is a diagram showing a structure of a refrigeration cycle apparatus according to embodiment 5.

Fig. 20 is a flowchart for explaining the processing executed by the control device in embodiment 5.

Fig. 21 is a p-h diagram for explaining a change in the refrigeration cycle in embodiment 5.

Fig. 22 is a diagram showing a configuration of a refrigeration cycle apparatus according to embodiment 6.

Fig. 23 is a flowchart for explaining the processing executed by the control device in embodiment 6.

Fig. 24 is a p-h diagram for explaining a change in the refrigeration cycle in embodiment 6.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following description will be given of a plurality of embodiments, but the configurations described in the embodiments are appropriately combined from the start of the application. In the drawings, the same or corresponding portions are denoted by the same reference numerals, and the description thereof will not be repeated. In the following drawings, the size relationship of each component may be different from the actual one.

Embodiment 1.

Fig. 1 is a diagram showing a configuration of a refrigeration cycle apparatus according to embodiment 1. The refrigeration cycle apparatus 100 includes a refrigerant circuit 80 including a compressor 10, an indoor heat exchanger 20, an expansion valve LEV1, an outdoor heat exchanger 40, pipes 51 to 56, and a four-way valve 50. The four-way valve 50 has ports P1 to P4.

The pipe 51 is connected between the discharge port of the compressor 10 and the port P1 of the four-way valve 50. The pipe 52 is connected between the port P3 of the four-way valve 50 and the port P1 of the indoor heat exchanger 20. The pipe 53 is connected between the indoor heat exchanger 20 and the expansion valve LEV1. The piping 54 is connected between the LEV1 and the outdoor heat exchanger 40.

The pipe 55 is connected between the port P2 of the outdoor heat exchanger 40 and the port P4 of the four-way valve 50. The pipe 56 is connected between the suction port of the compressor 10 and the port P2 of the four-way valve 50.

The compressor 10 is configured to change an operation frequency by a control signal received from a control device not shown. Specifically, the compressor 10 incorporates a drive motor whose rotation speed is variable controlled by an inverter, and when the operation frequency is changed, the rotation speed of the drive motor is changed. The output of the compressor 10 is adjusted by changing the operating frequency of the compressor 10. As the compressor 10, various types of compressors can be employed, for example, a rotary type, a reciprocating type, a scroll type, a screw type, and the like.

The four-way valve 50 is controlled to be in either a cooling operation state or a heating operation state by a control signal received from a control device not shown. As shown by the solid line, the heating operation state is a state in which the port P1 communicates with the port P3 and the port P2 communicates with the port P4. The cooling operation state is a state in which the port P1 communicates with the port P4 and the port P2 communicates with the port P3 as indicated by the broken line.

By operating the compressor 10 in the heating operation state, the refrigerant circulates through the refrigerant circuit in the order of the compressor 10, the indoor heat exchanger 20, the LEV1, the outdoor heat exchanger 40, and the compressor 10. In addition, by operating the compressor 10 in the cooling operation state, the refrigerant circulates through the refrigerant circuit in the order of the compressor 10, the outdoor heat exchanger 40, the LEV1, the indoor heat exchanger 20, and the compressor 10.

Fig. 2 is a p-h diagram of a refrigeration cycle apparatus in a study example using an azeotropic refrigerant. Fig. 3 is a view showing a frosting zone of the outdoor heat exchanger in a study example using an azeotropic refrigerant.

As shown in fig. 2, when the azeotropic refrigerant is used, there is no temperature rise in the two-phase region, and therefore, in the low-temperature and high-humidity heating operation, frost is uniformly formed on the front surface of the outdoor heat exchanger 40 where the intake air contacts. In this case, the air passage is narrowed by the frost formation, and the volume of the blown air from the outdoor heat exchanger 40 is reduced. Therefore, defrosting needs to be frequently performed before the air passage is blocked, and the defrosting cycle is short.

Fig. 4 is a p-h diagram of the refrigeration cycle apparatus of the present embodiment using a non-azeotropic refrigerant. Fig. 5 is a diagram showing the structure and frosting area of the outdoor heat exchanger of the present embodiment using a non-azeotropic refrigerant. Fig. 6 is a view of the outdoor heat exchanger shown in fig. 5, as seen from the front.

As shown in the p-h diagram of fig. 4, when a non-azeotropic refrigerant is used, the isotherm has an inclination in the two-phase region, and therefore, even if the temperature of the refrigerant inflow portion of the outdoor heat exchanger 40 is-5 ℃ during the heating operation, the temperature of the refrigerant outlet portion can be 0.5 ℃. This means that the temperature of a part of the outdoor heat exchanger 40 can be set to 0 ℃ or higher. In the present embodiment, in the low-temperature and high-humidity heating operation in which the outside air temperature is around 2 ℃, the refrigeration cycle apparatus is operated so as to have the temperature distribution shown in fig. 4.

As shown in fig. 5, the refrigerant flows into the outdoor heat exchanger 40 from the pipe 54, and the refrigerant flows out from the outdoor heat exchanger 40 to the pipe 55. When the suction air side is the front surface, the outdoor heat exchanger 40 has the 1 st row of fin groups L1 on the front surface and the 2 nd row of fin groups L2 on the back surface. Each of the fin groups L1 and L2 is formed by arranging 6 pipes serving as refrigerant passages in parallel, and the pipes are connected to the side surfaces thereof. The 6 pipes are referred to as heat pipes R1 to R6 in the fin group L1 in order from top to bottom, and the 6 pipes are referred to as heat pipes R7 to R12 in the fin group L2 in order from bottom to top.

As shown in fig. 5 and 6, the refrigerant flows from the right side of the uppermost heat transfer tube R1 of the 1 st row of fin groups L1, flows from right to left through the heat transfer tube R1, flows from left to right through the connection pipe C12, and reciprocates once through the heat transfer tube R2.

The refrigerant flowing out of the heat transfer pipe R2 flows through the connection pipe C23 from right to left in the heat transfer pipe R3. Then, the refrigerant flows through the heat transfer pipe R4 from left to right via the connection pipe C34, and the refrigerant reciprocates once again.

The refrigerant flowing out of the heat pipe R4 flows through the connection pipe C45 from right to left in the heat pipe R5. Then, the refrigerant flows through the heat transfer pipe R6 from left to right via the connection pipe C56, and the refrigerant reciprocates once again.

Similarly, the heat transfer pipes R7 to R12 shown in fig. 5 reciprocate three times in the left-right direction of fig. 6. However, the heat transfer pipes R7 to R12 are different from the heat transfer pipes R1 to R6 in that the refrigerant flows from the lower layer upward in order.

That is, the refrigerant flowing out of the heat transfer pipe R6 flows through the connection pipe C67 from the right side to the left side in fig. 6 in the heat transfer pipe R7. Then, the refrigerant flows through the heat transfer pipe R8 from left to right via the connection pipe, and the refrigerant reciprocates once again.

The refrigerant flowing out of the heat transfer pipe R8 flows through the connection pipe C89 in the heat transfer pipe R9 from the right side to the left side in fig. 6. Then, the refrigerant flows through the heat transfer pipe R10 from left to right via the connection pipe, and reciprocates once more.

The refrigerant flowing out of the heat transfer pipe R10 flows through the connection pipe C1011 from the right side to the left side in fig. 6 in the heat transfer pipe R11. Then, the refrigerant flows through the heat transfer pipe R12 from left to right via the connection pipe, and the refrigerant reciprocates once again, and is sent to the pipe 55.

When the non-azeotropic refrigerant is applied to the outdoor heat exchanger 40 having the above-described configuration, the heating operation at a low temperature and a high humidity around the outside air temperature of 2 ℃ can be divided into a frosting area A1 where frost is likely to adhere and a non-frosting area A2 where frost is not likely to adhere. Therefore, even if the air volume of the blown air is reduced in the frosting zone A1, the air volume of the blown air can be ensured in the non-frosting zone A2. In this way, by frosting the outdoor heat exchanger 40 with a bias, the defrosting cycle can be prolonged.

Fig. 7 is a diagram for explaining a difference in defrosting cycle between a study example and the refrigeration cycle apparatus of the present embodiment. Fig. 7 shows the capacity J0, the compressor frequency F0, and the frosting amount G0 of the refrigeration cycle apparatus of the comparative example shown in fig. 2 and 3, and the capacity J1, the compressor frequency F1, and the frosting amount G1 of the refrigeration cycle apparatus of the present embodiment shown in fig. 4 to 6.

When the entire surface is frosted as in the comparative example, the frosting amount G0 > G1 is from time t0 to t 1. In order to secure the necessary capacity in association with this, the compressor frequency F0 reaches the maximum frequency (upper limit frequency) at time t 1. Therefore, as the frosting quantity G0 increases from time t1 to t3, the capacity J0 decreases in advance, and at time t3, defrosting is required and defrosting starts.

In contrast, in the present embodiment, the frosting quantity G1 is smaller than the frosting quantity G0, and the compressor frequency F1 reaches the upper limit at a time t2 after the time t 1. Therefore, the capacity J1 falls to a value at which defrosting needs to be started, also at t4 after time t 3. Since the defrosting time after that is substantially constant in the case of the comparative example and in the case of the present embodiment, the present embodiment in which the heating operation time is long has a longer defrosting cycle than the comparative example. Therefore, in the refrigeration cycle apparatus of the present embodiment, the load-side comfort is improved and the average COP is improved due to the extension of the defrosting cycle.

Embodiment 2.

Fig. 8 is a diagram showing a configuration of a refrigeration cycle apparatus according to embodiment 2. The refrigeration cycle apparatus 110 shown in fig. 8 includes a control device 90 and a temperature sensor 111 in addition to the configuration of the refrigeration cycle apparatus 100 shown in fig. 1. Other structures are illustrated in fig. 1, and thus, the description thereof will not be repeated here.

The control device 90 includes a CPU (Central Processing Unit: central processing unit) 91, a Memory 92 (ROM (Read Only Memory) and RAM (Random Access Memory: random access Memory)), and an input/output buffer (not shown). The CPU91 expands and executes programs stored in the ROM in the RAM or the like. The program stored in the ROM is a program in which the processing steps of the control device 90 are described. The control device 90 executes control of each device in the refrigeration cycle device 110 according to these programs. The control is not limited to the software-based processing, but can be performed by dedicated hardware (electronic circuit). In particular, the control device 90 is configured to control the LEV1 based on the output of the temperature sensor 111.

Fig. 9 is a diagram for explaining the configuration of the temperature sensor 111. Fig. 9 shows a case where the outdoor heat exchanger 40 shown in fig. 5 is provided with a temperature sensor 111. The outdoor heat exchanger 40 is illustrated in fig. 4 to 6, and thus, the description thereof will not be repeated here.

The temperature sensor 111 is disposed at the boundary between the portion of the outdoor heat exchanger 40 that is intended to be the frosting area A1 and the portion that is intended to be the non-frosting area A2. Then, if the refrigeration cycle apparatus is controlled so that the temperature detected by the temperature sensor 111 becomes 0 ℃, frost adheres to the frosting zone A1 and does not adhere to the non-frosting zone A2 during the heating operation at the time of low temperature and high humidity, and therefore ventilation in the non-frosting zone A2 can be ensured, and the defrosting cycle can be prolonged appropriately. The boundaries of the frosting zone A1 and the non-frosting zone A2 can be experimentally decided in advance so as to be suitable for performing low-load heating at low temperature and low humidity.

Fig. 10 is a diagram for explaining the determination of the mounting position of the temperature sensor 111. As shown by the solid line in fig. 10, the relationship between the frosting area and the capacity at the maximum frequency under the low-temperature and high-humidity operation condition was obtained in advance. The mounting position of the temperature sensor 111 is determined such that the area of the frosting zone A1 becomes a frosting area S (A1) that is necessary for the low-temperature and high-humidity operation.

Fig. 11 is a flowchart for explaining the processing executed by the control device in embodiment 2. The control device 90 determines whether or not the temperature Tsen detected by the temperature sensor 111 attached to the outdoor heat exchanger 40 is lower than the frosting temperature Tfro (step S1). The frosting temperature Tfro can be set to 0 ℃.

During a period when Tsen < Tfro does not hold (no in S1), control device 90 repeats the process of step S1. When Tsen < Tpro is satisfied (YES in S1), control device 90 increases the opening degree of LEV1 so that Tsen. Gtoreq. Tpro (S2).

Fig. 12 is a p-h diagram for explaining a change in the refrigeration cycle in embodiment 2. In step S2, when the opening degree of LEV1 is increased, the degree of supercooling of the load side heat exchanger outlet decreases, and the refrigeration cycle changes from the state shown by the solid line CY1 to the state shown by the broken line CY2 on the p-h line diagram.

At this time, before the compressor frequency F reaches the maximum value Fmax (no in S3), the control device 90 adjusts the compressor frequency F (S5) so that the heating capacity Q becomes the target heating capacity Qtar, and executes the processing from step S1 again.

On the other hand, when the compressor frequency F reaches the maximum value Fmax (yes in S3), the target capacity is not reached, and therefore, the control device 90 performs the defrosting determination. Whether or not defrosting is necessary can be determined based on the continuous operation time of heating, the allowable capacity drop ratio (low-pressure portion refrigerant pressure drop) at the time of heating, and the like.

If defrosting is not necessary (no in S4), the control device 90 executes the processing from step S1 again. When defrosting is required (yes in S4), the control device 90 starts the defrosting operation.

As described above, in the refrigeration cycle apparatus according to embodiment 2, in the low-temperature and high-humidity heating operation, the enthalpy of the refrigerant inlet of the outdoor heat exchanger 40 is increased, and the temperature is raised by the temperature gradient of the non-azeotropic refrigerant. This frosts only a partial area of the outdoor heat exchanger 40, and thus the defrosting cycle is prolonged. In particular, the temperature sensor 111 is disposed at the boundary portion between the frosting region and the non-frosting region of the outdoor heat exchanger 40, and thus the frosting region can be accurately controlled.

Embodiment 3.

Fig. 13 is a diagram showing a configuration of a refrigeration cycle apparatus according to embodiment 3. In the refrigeration cycle apparatus 120 shown in fig. 13, the refrigerant circuit 80 includes an internal heat exchanger 121 and an expansion valve LEV2 in addition to the configuration of the refrigeration cycle apparatus 110 of fig. 8. A part of the refrigerant flowing through the pipe 53 is branched to the bypass passage 61, depressurized by the expansion valve LEV2, and returned to the compressor 10. In fig. 13, the refrigerant is returned to the intermediate pressure port of the compressor 10, but the bypass passage may be configured to return the refrigerant to the suction port of the compressor 10. The interior heat exchanger 121 is configured to exchange heat between the refrigerant flowing out of the indoor heat exchanger 20 and the refrigerant depressurized by the expansion valve LEV2 in the bypass flow path 61. Other structures are illustrated in fig. 8, and thus, the description is not repeated here.

Fig. 14 is a flowchart for explaining the processing executed by the control device in embodiment 3. The processing of the flowchart of fig. 14 includes step S12 instead of step S2 in the processing of the flowchart of fig. 11. The other processing is described with reference to fig. 11, and therefore, step S12 will be described here.

In the process of fig. 11, the opening degree of LEV1 is increased so as to be Tsen not less than Tfro detected by the temperature sensor 111 (S2), but in the process of fig. 14, when Tsen < Tfro is obtained (yes in S1), the opening degree of LEV2 is decreased so as to be Tsen not less than Tfro (S12).

Fig. 15 is a p-h diagram for explaining a change in the refrigeration cycle in embodiment 3. In step S12, when the opening degree of LEV2 is reduced, the degree of supercooling at the outlet of the internal heat exchanger 121 is reduced, and the refrigeration cycle is changed from the state shown by the solid line CY11 to the state shown by the broken line CY12 on the p-h diagram.

In this way, in embodiment 3, by changing the opening degree of LEV2, the portion where the temperature sensor 111 is disposed is kept near 0 ℃, and the boundary between the frosting zone A1 and the non-frosting zone A2 is kept as intended.

Then, when the compressor frequency F becomes the maximum value Fmax and the target capacity is not reached during operation, the defrosting operation is started after the defrosting determination (S4).

By adopting the configuration and control as in embodiment 3, it is possible to defrost only a partial area of the outdoor heat exchanger 40 and to lengthen the defrosting cycle.

Embodiment 4.

Fig. 16 is a diagram showing a structure of a refrigeration cycle apparatus according to embodiment 4. In the refrigeration cycle apparatus 130 shown in fig. 16, the refrigerant circuit 80 includes the bypass flow path 62 and the expansion valve LEV3 in addition to the configuration of the refrigeration cycle apparatus 110 shown in fig. 8. A part of the exhaust gas refrigerant flowing through the pipe 51 is branched at a branch point BP2 into the bypass flow path 62, the flow rate is adjusted by the expansion valve LEV3, and the refrigerant merges with the pipe 54 at a merging point MP 2. Other structures are illustrated in fig. 8, and thus, the description thereof will not be repeated here.

Fig. 17 is a flowchart for explaining the processing executed by the control device in embodiment 4. The processing of the flowchart of fig. 17 includes step S22 instead of step S2 in the processing of the flowchart of fig. 11. The other part of the processing is described in fig. 11, and therefore step S22 will be described here.

In the process of fig. 11, the opening degree of LEV1 is increased so as to be Tsen not less than Tfro detected by the temperature sensor 111 (S2), but in the process of fig. 17, when Tsen < Tfro is obtained (yes in S1), the opening degree of LEV3 is increased so as to be Tsen not less than Tfro (S22).

Fig. 18 is a p-h diagram for explaining a change in the refrigeration cycle in embodiment 4. In step S22, when the opening degree of the LEV3 is increased, the refrigerant in the bypass flow path 62, which merges with the two-phase refrigerant flowing into the outdoor heat exchanger 40, increases, and the temperature of the inlet portion of the outdoor heat exchanger 40 increases. In the refrigeration cycle, as indicated by arrows CY21 and CY22 on the p-h diagram shown in fig. 18, a part of the exhaust gas merges with the refrigerant, and the specific enthalpy of the refrigerant in the inlet portion of the outdoor heat exchanger 40 also increases.

In this way, in embodiment 4, by changing the opening degree of LEV3, the portion where the temperature sensor 111 is disposed is kept near 0 ℃, and the boundary between the frosting zone A1 and the non-frosting zone A2 is kept as intended.

By adopting the configuration and control as in embodiment 4, it is possible to defrost only a partial area of the outdoor heat exchanger 40 and to lengthen the defrosting cycle.

Embodiment 5.

Fig. 19 is a diagram showing a structure of a refrigeration cycle apparatus according to embodiment 5. In the refrigeration cycle apparatus 140 shown in fig. 19, the refrigerant circuit 80 includes a heater 141 in addition to the configuration of the refrigeration cycle apparatus 110 shown in fig. 8. The heater 141 can heat the refrigerant flowing through the pipe 54. Other structures are illustrated in fig. 8, and thus, the description thereof will not be repeated here.

Fig. 20 is a flowchart for explaining the processing executed by the control device in embodiment 5. The processing of the flowchart of fig. 20 includes step S32 instead of step S2 in the processing of the flowchart of fig. 11. The other part of the processing is described in fig. 11, and therefore step S32 will be described here.

In the process of fig. 11, the opening degree of LEV1 is increased so as to be Tsen not less than Tfro detected by the temperature sensor 111 (S2), but in the process of fig. 20, when Tsen < Tfro is obtained (yes in S1), the heating amount of the heater 141 is increased so as to be Tsen not less than Tfro (S32).

Fig. 21 is a p-h diagram for explaining a change in the refrigeration cycle in embodiment 5. In step S32, when the heating amount of the heater 141 is increased, the temperature of the refrigerant flowing into the outdoor heat exchanger 40 increases, and the temperature of the inlet portion of the outdoor heat exchanger 40 increases. The refrigeration cycle changes from CY31 to CY32 on the p-h diagram shown in fig. 21, and the specific enthalpy of the refrigerant at the inlet portion of the outdoor heat exchanger 40 also increases as indicated by the arrow in the figure.

In this way, in embodiment 5, by changing the heating amount of the heater 141, the portion where the temperature sensor 111 is disposed is kept near 0 ℃, and the boundary between the frosting zone A1 and the non-frosting zone A2 is kept as intended.

By adopting the configuration and control as in embodiment 5, it is possible to defrost only a partial area of the outdoor heat exchanger 40 and to lengthen the defrosting cycle.

Embodiment 6.

Fig. 22 is a diagram showing a configuration of a refrigeration cycle apparatus according to embodiment 6. In the refrigeration cycle apparatus 150 shown in fig. 22, the refrigerant circuit 80 includes a three-way valve 152 and an internal heat exchanger 151 in addition to the configuration of the refrigeration cycle apparatus 110 shown in fig. 8. The three-way valve 152 is provided midway in the pipe 51, and is a flow path switching device for switching whether the refrigerant discharged from the compressor 10 is directly sent to the port P1 of the four-way valve or sent through the internal heat exchanger 151, in response to a control signal from the control device 90. The internal heat exchanger 151 is configured to exchange heat between the refrigerant flowing through the pipe 54 and the refrigerant sent from the compressor 10 via the three-way valve 152. Other structures are illustrated in fig. 8, and thus, the description thereof will not be repeated here.

Fig. 23 is a flowchart for explaining the processing executed by the control device in embodiment 6. The processing of the flowchart of fig. 23 is the processing of the flowchart shown in fig. 11, and includes step S42 instead of step S2. The other part of the processing is described in fig. 11, and therefore step S42 is described here.

In the process of fig. 11, the opening degree of LEV1 is increased so that Tsen detected by the temperature sensor 111 becomes equal to or greater than Tfro (S2), but in the process of fig. 20, when Tsen < Tfro is reached (yes in S1), the three-way valve 152 is switched so that the refrigerant discharged from the compressor 10 flows into the internal heat exchanger 151 (S42). Thus, the state of the refrigerant circuit 80 is set to a state where Tsen is equal to or greater than Tfro, or a state close to such a state.

Fig. 24 is a p-h diagram for explaining a change in the refrigeration cycle in embodiment 6. In step S42, when the three-way valve 152 is switched so that the discharge refrigerant is introduced into the internal heat exchanger 151, the refrigeration cycle changes as indicated from CY41 to CY42 on the p-h diagram shown in fig. 24. That is, as indicated by the arrow CY42A, the refrigerant discharged from the compressor 10 releases heat before flowing into the indoor heat exchanger 20. Since the refrigerant having passed the LEV1 receives this heat as indicated by the arrow CY42B, the temperature of the refrigerant flowing into the outdoor heat exchanger 40 increases.

In this way, in embodiment 6, the transport destination of the discharged refrigerant is changed so as to pass through the internal heat exchanger 151, whereby the portion where the temperature sensor 111 is disposed is kept near 0 ℃, and the boundary between the frosting zone A1 and the non-frosting zone A2 is kept as intended.

By adopting the configuration and control as in embodiment 6, it is possible to defrost only a partial area of the outdoor heat exchanger 40 and to lengthen the defrosting cycle.

(summary)

The above embodiments are summarized again with reference to the drawings.

The present invention relates to a refrigeration cycle apparatus 100. The refrigeration cycle apparatus 100 shown in fig. 1 includes: a refrigerant circuit 80 in which the compressor 10, the indoor heat exchanger 20 (condenser), the 1 st expansion valve LEV1, and the outdoor heat exchanger 40 (evaporator) are connected by refrigerant pipes 51 to 56; and a non-azeotropic refrigerant flowing through the refrigerant pipes 51 to 56. When the non-azeotropic refrigerant passes through the outdoor heat exchanger 40 (evaporator), a temperature difference occurs between the inlet and the outlet of the outdoor heat exchanger 40 (evaporator). As shown in fig. 5 and 6, the outdoor heat exchanger 40 (evaporator) includes: fin groups L1, L2 stacked with a gap therebetween; and heat transfer tubes R1 to R12 penetrating the fin groups L1, L2 in the stacking direction of the fin groups L1, L2, for the zeotropic refrigerant to flow therein. The fin groups L1 and L2 include: a1 st fin portion (frosting area A1) capable of adhering frost in a wet environment; and A2 nd fin portion (non-frosting area A2) which ensures ventilation without adhering frost.

Preferably, the refrigeration cycle apparatus 100 further includes a control device 90 that controls the refrigerant circuit 80. As described with reference to fig. 4 and 5, the control device 90 controls the refrigerant circuit 80 such that the temperature of the non-azeotropic refrigerant flowing through the portion of the heat transfer pipe penetrating the 1 st fin portion (heat transfer pipes R1 to R3) is 0 degrees or less, and the temperature of the non-azeotropic refrigerant flowing through the heat transfer pipe of the 2 nd fin portion (heat transfer pipes R4 to R12) is 0 degrees or more.

As shown in fig. 8 and 9, the 1 st fin portion is preferably disposed in a predetermined frosting area A1 in the outdoor heat exchanger 40 (evaporator). The 2 nd fin portion is disposed in a predetermined non-frosting area A2 in the outdoor heat exchanger 40 (evaporator). The refrigeration cycle device 110 further includes a temperature sensor 111 disposed at the boundary between the frosting zone A1 and the non-frosting zone A2 in the outdoor heat exchanger 40 (evaporator). The control device 90 is configured to control the opening degree of the 1 st expansion valve LEV1 based on the output of the temperature sensor 111 so that the temperature of the boundary between the frosting zone A1 and the non-frosting zone A2 becomes 0 ℃.

In the refrigeration cycle apparatus 120 shown in fig. 13, the refrigerant circuit 80 preferably further includes: a bypass flow path 61 that branches from a refrigerant pipe 53 connecting the indoor heat exchanger 20 (condenser) and the 1 st expansion valve LEV1 at a branch point BP1 and returns the refrigerant to the compressor 10; a2 nd expansion valve LEV2 disposed in the bypass flow path 61; and an internal heat exchanger 121 that performs heat exchange between the refrigerant flowing from the indoor heat exchanger 20 (condenser) toward the branch point BP1 and the refrigerant passing through the 2 nd expansion valve LEV2.

As shown in fig. 8 and 9, the 1 st fin portion is preferably disposed in a predetermined frosting area A1 in the outdoor heat exchanger 40 (evaporator). The 2 nd fin portion is disposed in a predetermined non-frosting area A2 in the outdoor heat exchanger 40 (evaporator). The refrigeration cycle apparatus 120 shown in fig. 13 further includes a temperature sensor 111 disposed at the boundary between the frosting zone A1 and the non-frosting zone A2 in the outdoor heat exchanger 40 (evaporator). As shown in fig. 14, the control device 90 is configured to control the opening degree of the 2 nd expansion valve LEV2 based on the output of the temperature sensor 111 so that the temperature of the boundary between the frosting zone A1 and the non-frosting zone A2 becomes 0 ℃.

In the refrigeration cycle apparatus 130 shown in fig. 16, the refrigerant circuit 80 preferably further includes: a bypass flow path 62 branching from a refrigerant pipe between the discharge port of the compressor 10 and the indoor heat exchanger 20 (condenser) and merging with a refrigerant pipe connecting the 1 st expansion valve LEV1 and the outdoor heat exchanger 40 (evaporator); and an expansion valve LEV3 that functions as a flow rate adjustment valve disposed in the bypass flow path 62.

More preferably, as shown in fig. 8 and 9, the 1 st fin portion is disposed in a predetermined frosting area A1 in the outdoor heat exchanger 40 (evaporator). The 2 nd fin portion is disposed in a predetermined non-frosting area A2 in the outdoor heat exchanger 40 (evaporator). The refrigeration cycle apparatus 130 shown in fig. 16 further includes a temperature sensor 111 disposed at the boundary between the frosting zone A1 and the non-frosting zone A2 in the outdoor heat exchanger 40 (evaporator). As shown in fig. 17, the control device 90 is configured to control the opening degree of the LEV3 such that the temperature of the boundary between the frosting zone A1 and the non-frosting zone A2 becomes 0 ℃ based on the output of the temperature sensor 111.

In the refrigeration cycle apparatus 140 shown in fig. 19, the refrigerant circuit 80 preferably further includes a heater 141 for heating the refrigerant flowing through the refrigerant pipe 54 connecting the 1 st expansion valve LEV1 and the outdoor heat exchanger 40 (evaporator).

More preferably, as shown in fig. 8 and 9, the 1 st fin portion is disposed in a predetermined frosting area A1 in the outdoor heat exchanger 40 (evaporator). The 2 nd fin portion is disposed in a predetermined non-frosting area A2 in the outdoor heat exchanger 40 (evaporator). The refrigeration cycle apparatus 140 shown in fig. 19 further includes a temperature sensor 111 disposed at the boundary between the frosting zone A1 and the non-frosting zone A2 in the outdoor heat exchanger 40 (evaporator). The control device 90 is configured to control the heating amount of the heater 141 based on the output of the temperature sensor 111 so that the temperature of the boundary between the frosting zone A1 and the non-frosting zone A2 becomes 0 ℃.

In the refrigeration cycle apparatus 150 shown in fig. 22, it is preferable that the refrigerant pipe 51 that is a part of the refrigerant pipe connecting the discharge port of the compressor 10 and the indoor heat exchanger 20 (condenser) is provided with a1 st flow path 51A and a2 nd flow path 51B provided in parallel with the 1 st flow path 51A. The refrigerant circuit 80 further includes: an internal heat exchanger 151 that exchanges heat between the refrigerant flowing from the 1 st expansion valve LEV1 toward the outdoor heat exchanger 40 (evaporator) and the refrigerant flowing in the 2 nd flow path 51B; and a three-way valve 152 that switches whether the refrigerant discharged from the compressor 10 flows to the 1 st flow path 51A or the 2 nd flow path 51B.

More preferably, as shown in fig. 8 and 9, the 1 st fin portion is disposed in a predetermined frosting area A1 in the outdoor heat exchanger 40 (evaporator). The 2 nd fin portion is disposed in a predetermined non-frosting area A2 in the outdoor heat exchanger 40 (evaporator). The refrigeration cycle apparatus 150 shown in fig. 22 further includes a temperature sensor 111 disposed at the boundary between the frosting zone A1 and the non-frosting zone A2 in the outdoor heat exchanger 40 (evaporator). As shown in fig. 23, the control device 90 is configured to control the three-way valve 152 so that the temperature of the boundary between the frosting zone A1 and the non-frosting zone A2 becomes 0 ℃ based on the output of the temperature sensor 111.

The refrigeration cycle apparatus 100 preferably further includes a four-way valve 50 that can be connected to the refrigerant circuit 80 by exchanging the discharge port and the suction port of the compressor 10. The four-way valve 50 can switch the flow direction of the refrigerant flowing through the refrigerant circuit 80 to the 1 st direction in which the refrigerant flows through the compressor 10, the indoor heat exchanger 20 (condenser), the 1 st expansion valve LEV1, and the outdoor heat exchanger 40 (evaporator), and the 2 nd direction in which the refrigerant flows through the compressor 10, the outdoor heat exchanger 40 (evaporator), the 1 st expansion valve LEV1, and the indoor heat exchanger 20 (condenser).

With the above configuration, since the defrosting cycle can be prolonged by biased frosting, the load-side comfort can be improved. Further, the average COP increases by the cumulative heating capacity increase.

The embodiments disclosed herein are merely illustrative in all respects and should not be considered restrictive. The scope of the present invention is shown by the claims, and not the description of the embodiments described above, but all changes within the meaning and scope equivalent to the claims are encompassed.

Description of the reference numerals

10 compressors, 20, 40, 121, 151 heat exchangers, 50 four-way valves, 51 to 56 piping, 51A 1 st flow path, 51B 2 nd flow path, 61, 62 bypass flow paths, 80 refrigerant circuits, 90 control devices, 91CPU,92 memories, 100, 110, 120, 130, 140, 150 refrigeration cycle devices, 111 temperature sensors, 141 heater, 152 three-way valve, A1 frosting area, A2 non-frosting area, BP1, BP2 branch point, C12, C23, C34, C45, C56, C67, C89, C1011 connecting piping, L1, L2 fin group, LEV1, LEV2, LEV3 expansion valve, P1, P2, P3, P4 port, R1-R12 heat conduction pipe.

Claims

1. A refrigeration cycle device is provided with:

a refrigerant circuit in which a compressor, a condenser, a1 st expansion valve, and an evaporator are connected by refrigerant piping; and

a non-azeotropic refrigerant flowing through the refrigerant pipe,

in the case where the zeotropic refrigerant passes through the evaporator, a temperature difference is generated between an inlet and an outlet of the evaporator,

the evaporator is provided with:

fin groups stacked at intervals; and

a heat pipe penetrating the fin group in a lamination direction of the fin group, wherein the zeotropic refrigerant flows in the heat pipe,

the fin group includes:

a1 st fin portion capable of adhering frost in a multi-wet environment; and

and a2 nd fin portion which ensures ventilation without adhering frost.

2. The refrigeration cycle apparatus according to claim 1, wherein,

the refrigeration cycle device further includes a control device for controlling the refrigerant circuit,

the control device controls the refrigerant circuit such that, when the temperature of air that exchanges heat with the evaporator is 0 ℃ or higher, the temperature of the zeotropic refrigerant flowing through the heat transfer tube penetrating the 1 st fin portion is 0 ℃ or lower, and the temperature of the zeotropic refrigerant flowing through the heat transfer tube of the 2 nd fin portion is 0 ℃ or higher and the temperature of the air or lower.

3. The refrigeration cycle apparatus according to claim 2, wherein,

the 1 st fin portion is disposed in the evaporator in a predetermined frosting area,

the 2 nd fin portion is disposed in a predetermined non-frosting region in the evaporator,

the refrigeration cycle device further includes a temperature sensor disposed in the evaporator at a boundary between the frosting region and the non-frosting region,

the control device is configured to control the opening degree of the 1 st expansion valve so that the temperature of the boundary becomes 0 ℃ based on the output of the temperature sensor.

4. The refrigeration cycle apparatus according to claim 2, wherein,

the refrigerant circuit further includes:

a bypass flow path branching from the refrigerant pipe connecting the condenser and the 1 st expansion valve at a branching point, and returning refrigerant to the compressor;

a2 nd expansion valve disposed in the bypass flow path; and

an internal heat exchanger that exchanges heat between the refrigerant flowing from the condenser toward the branch point and the refrigerant passing through the 2 nd expansion valve.

5. The refrigeration cycle apparatus according to claim 4, wherein,

the control device is configured to control the opening degree of the 2 nd expansion valve so that the temperature of the boundary becomes 0 ℃ based on the output of the temperature sensor.

6. The refrigeration cycle apparatus according to claim 2, wherein,

the refrigerant circuit further includes:

a bypass flow path branching from the refrigerant pipe between the discharge port of the compressor and the condenser, and merging with the refrigerant pipe between the 1 st expansion valve and the evaporator; and

and a flow rate adjustment valve disposed in the bypass flow path.

7. The refrigeration cycle apparatus according to claim 6, wherein,

the control device is configured to control the opening degree of the flow rate adjustment valve so that the temperature of the boundary becomes 0 ℃ based on the output of the temperature sensor.

8. The refrigeration cycle apparatus according to claim 2, wherein,

the refrigerant circuit further includes a heater for heating the refrigerant flowing through the refrigerant pipe connecting the 1 st expansion valve and the evaporator.

9. The refrigeration cycle apparatus according to claim 8, wherein,

the control device is configured to control the heating amount of the heater so that the temperature of the boundary becomes 0 ℃ based on the output of the temperature sensor.

10. The refrigeration cycle apparatus according to claim 2, wherein,

the refrigerant pipe connecting the discharge port of the compressor and the condenser includes:

a1 st flow path; and

a2 nd flow path provided in parallel with the 1 st flow path,

the refrigerant circuit further includes:

an internal heat exchanger that performs heat exchange between the refrigerant flowing from the 1 st expansion valve toward the evaporator and the refrigerant flowing in the 2 nd flow path; and

and a flow path switching device that switches whether the refrigerant discharged from the compressor flows to the 1 st flow path or the 2 nd flow path.

11. The refrigeration cycle apparatus according to claim 10, wherein,

the control device is configured to control the flow path switching device based on an output of the temperature sensor so that the temperature of the boundary becomes 0 ℃.

12. The refrigeration cycle apparatus according to any one of claims 1 to 11, wherein,

the refrigeration cycle device further includes a four-way valve capable of exchanging a discharge port and a suction port of the compressor and connecting the four-way valve to the refrigerant circuit,

the four-way valve is capable of switching the flow direction of the refrigerant flowing through the refrigerant circuit to a1 st direction flowing in the order of the compressor, the condenser, the 1 st expansion valve, and the evaporator, and a2 nd direction flowing in the order of the compressor, the evaporator, the 1 st expansion valve, and the condenser.